From 48e9743dd6483c5fd3f10c8e42c60d52d64b0e27 Mon Sep 17 00:00:00 2001 From: Vladimir Zapolskiy Date: Mon, 27 Jul 2015 17:30:50 +0300 Subject: i2c: core: add and export of_get_i2c_adapter_by_node() interface of_find_i2c_adapter_by_node() call requires quite often missing put_device(), and i2c_put_adapter() releases a device locked by i2c_get_adapter() only. In general module_put(adapter->owner) and put_device(dev) are not interchangeable. This is a common error reproduction scenario as a result of the misusage described above (for clearness this is run on iMX6 platform with HDMI and I2C bus drivers compiled as kernel modules): root@mx6q:~# lsmod | grep i2c i2c_imx 10213 0 root@mx6q:~# lsmod | grep dw_hdmi_imx dw_hdmi_imx 3631 0 dw_hdmi 11846 1 dw_hdmi_imx imxdrm 8674 3 dw_hdmi_imx,imx_ipuv3_crtc,imx_ldb drm_kms_helper 113765 5 dw_hdmi,imxdrm,imx_ipuv3_crtc,imx_ldb root@mx6q:~# rmmod dw_hdmi_imx root@mx6q:~# lsmod | grep i2c i2c_imx 10213 -1 ^^^^^ root@mx6q:~# rmmod i2c_imx rmmod: ERROR: Module i2c_imx is in use To fix existing users of these interfaces and to avoid any further confusion and misusage in future, add one more interface of_get_i2c_adapter_by_node(), it is similar to i2c_get_adapter() in sense that an I2C bus device driver found and locked by user can be correctly unlocked by i2c_put_adapter(). Signed-off-by: Vladimir Zapolskiy Signed-off-by: Wolfram Sang --- include/linux/i2c.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'include') diff --git a/include/linux/i2c.h b/include/linux/i2c.h index e83a738a3b87..e2c859b74f8b 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -638,6 +638,8 @@ extern struct i2c_client *of_find_i2c_device_by_node(struct device_node *node); /* must call put_device() when done with returned i2c_adapter device */ extern struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node); +/* must call i2c_put_adapter() when done with returned i2c_adapter device */ +struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node); #else static inline struct i2c_client *of_find_i2c_device_by_node(struct device_node *node) @@ -649,6 +651,11 @@ static inline struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node { return NULL; } + +static inline struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node) +{ + return NULL; +} #endif /* CONFIG_OF */ #endif /* _LINUX_I2C_H */ -- cgit v1.2.3-70-g09d2 From f5005f7835e0da9ea6f203f8acc356bef9b331da Mon Sep 17 00:00:00 2001 From: Wolfram Sang Date: Tue, 19 May 2015 17:40:55 +0200 Subject: dt-bindings: add header for generic I2C flags in bindings Tested-by: Andrey Danin Acked-by: Stephen Warren Signed-off-by: Wolfram Sang Signed-off-by: Wolfram Sang --- include/dt-bindings/i2c/i2c.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) create mode 100644 include/dt-bindings/i2c/i2c.h (limited to 'include') diff --git a/include/dt-bindings/i2c/i2c.h b/include/dt-bindings/i2c/i2c.h new file mode 100644 index 000000000000..1d5da81d90f1 --- /dev/null +++ b/include/dt-bindings/i2c/i2c.h @@ -0,0 +1,18 @@ +/* + * This header provides constants for I2C bindings + * + * Copyright (C) 2015 by Sang Engineering + * Copyright (C) 2015 by Renesas Electronics Corporation + * + * Wolfram Sang + * + * GPLv2 only + */ + +#ifndef _DT_BINDINGS_I2C_I2C_H +#define _DT_BINDINGS_I2C_I2C_H + +#define I2C_TEN_BIT_ADDRESS (1 << 31) +#define I2C_OWN_SLAVE_ADDRESS (1 << 30) + +#endif -- cgit v1.2.3-70-g09d2 From c5ebb387f4e6b2dd7c74d71caf7b696834d0c887 Mon Sep 17 00:00:00 2001 From: Wolfram Sang Date: Tue, 19 May 2015 17:44:31 +0200 Subject: i2c: add a flag to mark clients as slaves And update indentation with one more tab, sigh... Tested-by: Andrey Danin Acked-by: Stephen Warren Signed-off-by: Wolfram Sang Signed-off-by: Wolfram Sang --- include/linux/i2c.h | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'include') diff --git a/include/linux/i2c.h b/include/linux/i2c.h index e2c859b74f8b..5aea07137218 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -550,11 +550,12 @@ void i2c_lock_adapter(struct i2c_adapter *); void i2c_unlock_adapter(struct i2c_adapter *); /*flags for the client struct: */ -#define I2C_CLIENT_PEC 0x04 /* Use Packet Error Checking */ -#define I2C_CLIENT_TEN 0x10 /* we have a ten bit chip address */ +#define I2C_CLIENT_PEC 0x04 /* Use Packet Error Checking */ +#define I2C_CLIENT_TEN 0x10 /* we have a ten bit chip address */ /* Must equal I2C_M_TEN below */ -#define I2C_CLIENT_WAKE 0x80 /* for board_info; true iff can wake */ -#define I2C_CLIENT_SCCB 0x9000 /* Use Omnivision SCCB protocol */ +#define I2C_CLIENT_SLAVE 0x20 /* we are the slave */ +#define I2C_CLIENT_WAKE 0x80 /* for board_info; true iff can wake */ +#define I2C_CLIENT_SCCB 0x9000 /* Use Omnivision SCCB protocol */ /* Must match I2C_M_STOP|IGNORE_NAK */ /* i2c adapter classes (bitmask) */ -- cgit v1.2.3-70-g09d2 From b3fdd32799d834e2626fae087906e886037350c6 Mon Sep 17 00:00:00 2001 From: York Sun Date: Mon, 17 Aug 2015 11:53:48 -0700 Subject: i2c: mux: Add register-based mux i2c-mux-reg Based on i2c-mux-gpio driver, similarly the register-based mux switch from one bus to another by setting a single register. The register can be on PCIe bus, local bus, or any memory-mapped address. The endianness of such register can be specified in device tree if used, or in platform data. Signed-off-by: York Sun Acked-by: Alexander Sverdlin Signed-off-by: Wolfram Sang --- .../devicetree/bindings/i2c/i2c-mux-reg.txt | 74 ++++++ drivers/i2c/muxes/Kconfig | 11 + drivers/i2c/muxes/Makefile | 1 + drivers/i2c/muxes/i2c-mux-reg.c | 294 +++++++++++++++++++++ include/linux/platform_data/i2c-mux-reg.h | 44 +++ 5 files changed, 424 insertions(+) create mode 100644 Documentation/devicetree/bindings/i2c/i2c-mux-reg.txt create mode 100644 drivers/i2c/muxes/i2c-mux-reg.c create mode 100644 include/linux/platform_data/i2c-mux-reg.h (limited to 'include') diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-reg.txt b/Documentation/devicetree/bindings/i2c/i2c-mux-reg.txt new file mode 100644 index 000000000000..688783fbe696 --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c-mux-reg.txt @@ -0,0 +1,74 @@ +Register-based I2C Bus Mux + +This binding describes an I2C bus multiplexer that uses a single register +to route the I2C signals. + +Required properties: +- compatible: i2c-mux-reg +- i2c-parent: The phandle of the I2C bus that this multiplexer's master-side + port is connected to. +* Standard I2C mux properties. See mux.txt in this directory. +* I2C child bus nodes. See mux.txt in this directory. + +Optional properties: +- reg: this pair of specifies the register to control the mux. + The depends on its parent node. It can be any memory-mapped + address. The size must be either 1, 2, or 4 bytes. If reg is omitted, the + resource of this device will be used. +- little-endian: The existence indicates the register is in little endian. +- big-endian: The existence indicates the register is in big endian. + If both little-endian and big-endian are omitted, the endianness of the + CPU will be used. +- write-only: The existence indicates the register is write-only. +- idle-state: value to set the muxer to when idle. When no value is + given, it defaults to the last value used. + +Whenever an access is made to a device on a child bus, the value set +in the revelant node's reg property will be output to the register. + +If an idle state is defined, using the idle-state (optional) property, +whenever an access is not being made to a device on a child bus, the +register will be set according to the idle value. + +If an idle state is not defined, the most recently used value will be +left programmed into the register. + +Example of a mux on PCIe card, the host is a powerpc SoC (big endian): + + i2c-mux { + /* the depends on the address translation + * of the parent device. If omitted, device resource + * will be used instead. The size is to determine + * whether iowrite32, iowrite16, or iowrite8 will be used. + */ + reg = <0x6028 0x4>; + little-endian; /* little endian register on PCIe */ + compatible = "i2c-mux-reg"; + #address-cells = <1>; + #size-cells = <0>; + i2c-parent = <&i2c1>; + i2c@0 { + reg = <0>; + #address-cells = <1>; + #size-cells = <0>; + + si5338: clock-generator@70 { + compatible = "silabs,si5338"; + reg = <0x70>; + /* other stuff */ + }; + }; + + i2c@1 { + /* data is written using iowrite32 */ + reg = <1>; + #address-cells = <1>; + #size-cells = <0>; + + si5338: clock-generator@70 { + compatible = "silabs,si5338"; + reg = <0x70>; + /* other stuff */ + }; + }; + }; diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig index fdd0769c84a3..f06b0e24673b 100644 --- a/drivers/i2c/muxes/Kconfig +++ b/drivers/i2c/muxes/Kconfig @@ -61,4 +61,15 @@ config I2C_MUX_PINCTRL This driver can also be built as a module. If so, the module will be called pinctrl-i2cmux. +config I2C_MUX_REG + tristate "Register-based I2C multiplexer" + help + If you say yes to this option, support will be included for a + register based I2C multiplexer. This driver provides access to + I2C busses connected through a MUX, which is controlled + by a single register. + + This driver can also be built as a module. If so, the module + will be called i2c-mux-reg. + endmenu diff --git a/drivers/i2c/muxes/Makefile b/drivers/i2c/muxes/Makefile index 465778b5d5dc..e89799b76a92 100644 --- a/drivers/i2c/muxes/Makefile +++ b/drivers/i2c/muxes/Makefile @@ -7,5 +7,6 @@ obj-$(CONFIG_I2C_MUX_GPIO) += i2c-mux-gpio.o obj-$(CONFIG_I2C_MUX_PCA9541) += i2c-mux-pca9541.o obj-$(CONFIG_I2C_MUX_PCA954x) += i2c-mux-pca954x.o obj-$(CONFIG_I2C_MUX_PINCTRL) += i2c-mux-pinctrl.o +obj-$(CONFIG_I2C_MUX_REG) += i2c-mux-reg.o ccflags-$(CONFIG_I2C_DEBUG_BUS) := -DDEBUG diff --git a/drivers/i2c/muxes/i2c-mux-reg.c b/drivers/i2c/muxes/i2c-mux-reg.c new file mode 100644 index 000000000000..86d41d36a783 --- /dev/null +++ b/drivers/i2c/muxes/i2c-mux-reg.c @@ -0,0 +1,294 @@ +/* + * I2C multiplexer using a single register + * + * Copyright 2015 Freescale Semiconductor + * York Sun + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +struct regmux { + struct i2c_adapter *parent; + struct i2c_adapter **adap; /* child busses */ + struct i2c_mux_reg_platform_data data; +}; + +static int i2c_mux_reg_set(const struct regmux *mux, unsigned int chan_id) +{ + if (!mux->data.reg) + return -EINVAL; + + switch (mux->data.reg_size) { + case 4: + if (mux->data.little_endian) { + iowrite32(chan_id, mux->data.reg); + if (!mux->data.write_only) + ioread32(mux->data.reg); + } else { + iowrite32be(chan_id, mux->data.reg); + if (!mux->data.write_only) + ioread32(mux->data.reg); + } + break; + case 2: + if (mux->data.little_endian) { + iowrite16(chan_id, mux->data.reg); + if (!mux->data.write_only) + ioread16(mux->data.reg); + } else { + iowrite16be(chan_id, mux->data.reg); + if (!mux->data.write_only) + ioread16be(mux->data.reg); + } + break; + case 1: + iowrite8(chan_id, mux->data.reg); + if (!mux->data.write_only) + ioread8(mux->data.reg); + break; + default: + pr_err("Invalid register size\n"); + return -EINVAL; + } + + return 0; +} + +static int i2c_mux_reg_select(struct i2c_adapter *adap, void *data, + unsigned int chan) +{ + struct regmux *mux = data; + + return i2c_mux_reg_set(mux, chan); +} + +static int i2c_mux_reg_deselect(struct i2c_adapter *adap, void *data, + unsigned int chan) +{ + struct regmux *mux = data; + + if (mux->data.idle_in_use) + return i2c_mux_reg_set(mux, mux->data.idle); + + return 0; +} + +#ifdef CONFIG_OF +static int i2c_mux_reg_probe_dt(struct regmux *mux, + struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + struct device_node *adapter_np, *child; + struct i2c_adapter *adapter; + struct resource res; + unsigned *values; + int i = 0; + + if (!np) + return -ENODEV; + + adapter_np = of_parse_phandle(np, "i2c-parent", 0); + if (!adapter_np) { + dev_err(&pdev->dev, "Cannot parse i2c-parent\n"); + return -ENODEV; + } + adapter = of_find_i2c_adapter_by_node(adapter_np); + if (!adapter) + return -EPROBE_DEFER; + + mux->parent = adapter; + mux->data.parent = i2c_adapter_id(adapter); + put_device(&adapter->dev); + + mux->data.n_values = of_get_child_count(np); + if (of_find_property(np, "little-endian", NULL)) { + mux->data.little_endian = true; + } else if (of_find_property(np, "big-endian", NULL)) { + mux->data.little_endian = false; + } else { +#if defined(__BYTE_ORDER) ? __BYTE_ORDER == __LITTLE_ENDIAN : \ + defined(__LITTLE_ENDIAN) + mux->data.little_endian = true; +#elif defined(__BYTE_ORDER) ? __BYTE_ORDER == __BIG_ENDIAN : \ + defined(__BIG_ENDIAN) + mux->data.little_endian = false; +#else +#error Endianness not defined? +#endif + } + if (of_find_property(np, "write-only", NULL)) + mux->data.write_only = true; + else + mux->data.write_only = false; + + values = devm_kzalloc(&pdev->dev, + sizeof(*mux->data.values) * mux->data.n_values, + GFP_KERNEL); + if (!values) { + dev_err(&pdev->dev, "Cannot allocate values array"); + return -ENOMEM; + } + + for_each_child_of_node(np, child) { + of_property_read_u32(child, "reg", values + i); + i++; + } + mux->data.values = values; + + if (!of_property_read_u32(np, "idle-state", &mux->data.idle)) + mux->data.idle_in_use = true; + + /* map address from "reg" if exists */ + if (of_address_to_resource(np, 0, &res)) { + mux->data.reg_size = resource_size(&res); + if (mux->data.reg_size > 4) { + dev_err(&pdev->dev, "Invalid address size\n"); + return -EINVAL; + } + mux->data.reg = devm_ioremap_resource(&pdev->dev, &res); + if (IS_ERR(mux->data.reg)) + return PTR_ERR(mux->data.reg); + } + + return 0; +} +#else +static int i2c_mux_reg_probe_dt(struct gpiomux *mux, + struct platform_device *pdev) +{ + return 0; +} +#endif + +static int i2c_mux_reg_probe(struct platform_device *pdev) +{ + struct regmux *mux; + struct i2c_adapter *parent; + struct resource *res; + int (*deselect)(struct i2c_adapter *, void *, u32); + unsigned int class; + int i, ret, nr; + + mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL); + if (!mux) + return -ENOMEM; + + platform_set_drvdata(pdev, mux); + + if (dev_get_platdata(&pdev->dev)) { + memcpy(&mux->data, dev_get_platdata(&pdev->dev), + sizeof(mux->data)); + + parent = i2c_get_adapter(mux->data.parent); + if (!parent) + return -EPROBE_DEFER; + + mux->parent = parent; + } else { + ret = i2c_mux_reg_probe_dt(mux, pdev); + if (ret < 0) { + dev_err(&pdev->dev, "Error parsing device tree"); + return ret; + } + } + + if (!mux->data.reg) { + dev_info(&pdev->dev, + "Register not set, using platform resource\n"); + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + mux->data.reg_size = resource_size(res); + if (mux->data.reg_size > 4) { + dev_err(&pdev->dev, "Invalid resource size\n"); + return -EINVAL; + } + mux->data.reg = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(mux->data.reg)) + return PTR_ERR(mux->data.reg); + } + + mux->adap = devm_kzalloc(&pdev->dev, + sizeof(*mux->adap) * mux->data.n_values, + GFP_KERNEL); + if (!mux->adap) { + dev_err(&pdev->dev, "Cannot allocate i2c_adapter structure"); + return -ENOMEM; + } + + if (mux->data.idle_in_use) + deselect = i2c_mux_reg_deselect; + else + deselect = NULL; + + for (i = 0; i < mux->data.n_values; i++) { + nr = mux->data.base_nr ? (mux->data.base_nr + i) : 0; + class = mux->data.classes ? mux->data.classes[i] : 0; + + mux->adap[i] = i2c_add_mux_adapter(mux->parent, &pdev->dev, mux, + nr, mux->data.values[i], + class, i2c_mux_reg_select, + deselect); + if (!mux->adap[i]) { + ret = -ENODEV; + dev_err(&pdev->dev, "Failed to add adapter %d\n", i); + goto add_adapter_failed; + } + } + + dev_dbg(&pdev->dev, "%d port mux on %s adapter\n", + mux->data.n_values, mux->parent->name); + + return 0; + +add_adapter_failed: + for (; i > 0; i--) + i2c_del_mux_adapter(mux->adap[i - 1]); + + return ret; +} + +static int i2c_mux_reg_remove(struct platform_device *pdev) +{ + struct regmux *mux = platform_get_drvdata(pdev); + int i; + + for (i = 0; i < mux->data.n_values; i++) + i2c_del_mux_adapter(mux->adap[i]); + + i2c_put_adapter(mux->parent); + + return 0; +} + +static const struct of_device_id i2c_mux_reg_of_match[] = { + { .compatible = "i2c-mux-reg", }, + {}, +}; +MODULE_DEVICE_TABLE(of, i2c_mux_reg_of_match); + +static struct platform_driver i2c_mux_reg_driver = { + .probe = i2c_mux_reg_probe, + .remove = i2c_mux_reg_remove, + .driver = { + .name = "i2c-mux-reg", + }, +}; + +module_platform_driver(i2c_mux_reg_driver); + +MODULE_DESCRIPTION("Register-based I2C multiplexer driver"); +MODULE_AUTHOR("York Sun "); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:i2c-mux-reg"); diff --git a/include/linux/platform_data/i2c-mux-reg.h b/include/linux/platform_data/i2c-mux-reg.h new file mode 100644 index 000000000000..c68712aadf43 --- /dev/null +++ b/include/linux/platform_data/i2c-mux-reg.h @@ -0,0 +1,44 @@ +/* + * I2C multiplexer using a single register + * + * Copyright 2015 Freescale Semiconductor + * York Sun + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. + */ + +#ifndef __LINUX_PLATFORM_DATA_I2C_MUX_REG_H +#define __LINUX_PLATFORM_DATA_I2C_MUX_REG_H + +/** + * struct i2c_mux_reg_platform_data - Platform-dependent data for i2c-mux-reg + * @parent: Parent I2C bus adapter number + * @base_nr: Base I2C bus number to number adapters from or zero for dynamic + * @values: Array of value for each channel + * @n_values: Number of multiplexer channels + * @little_endian: Indicating if the register is in little endian + * @write_only: Reading the register is not allowed by hardware + * @classes: Optional I2C auto-detection classes + * @idle: Value to write to mux when idle + * @idle_in_use: indicate if idle value is in use + * @reg: Virtual address of the register to switch channel + * @reg_size: register size in bytes + */ +struct i2c_mux_reg_platform_data { + int parent; + int base_nr; + const unsigned int *values; + int n_values; + bool little_endian; + bool write_only; + const unsigned int *classes; + u32 idle; + bool idle_in_use; + void __iomem *reg; + resource_size_t reg_size; +}; + +#endif /* __LINUX_PLATFORM_DATA_I2C_MUX_REG_H */ -- cgit v1.2.3-70-g09d2 From 01eef96e37d77cd89156e5f51aab81a9d5c96539 Mon Sep 17 00:00:00 2001 From: Irina Tirdea Date: Wed, 12 Aug 2015 17:31:33 +0300 Subject: i2c: core: Add support for best effort block read emulation There are devices that need to handle block transactions regardless of the capabilities exported by the adapter. For performance reasons, they need to use i2c read blocks if available, otherwise emulate the block transaction with word or byte transactions. Add support for a helper function that would read a data block using the best transfer available: I2C_FUNC_SMBUS_READ_I2C_BLOCK, I2C_FUNC_SMBUS_READ_WORD_DATA or I2C_FUNC_SMBUS_READ_BYTE_DATA. Signed-off-by: Irina Tirdea Signed-off-by: Wolfram Sang --- drivers/i2c/i2c-core.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/i2c.h | 3 +++ 2 files changed, 60 insertions(+) (limited to 'include') diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index a6780289c61d..98f6c75b1d18 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -3007,6 +3007,63 @@ trace: } EXPORT_SYMBOL(i2c_smbus_xfer); +/** + * i2c_smbus_read_i2c_block_data_or_emulated - read block or emulate + * @client: Handle to slave device + * @command: Byte interpreted by slave + * @length: Size of data block; SMBus allows at most I2C_SMBUS_BLOCK_MAX bytes + * @values: Byte array into which data will be read; big enough to hold + * the data returned by the slave. SMBus allows at most + * I2C_SMBUS_BLOCK_MAX bytes. + * + * This executes the SMBus "block read" protocol if supported by the adapter. + * If block read is not supported, it emulates it using either word or byte + * read protocols depending on availability. + * + * The addresses of the I2C slave device that are accessed with this function + * must be mapped to a linear region, so that a block read will have the same + * effect as a byte read. Before using this function you must double-check + * if the I2C slave does support exchanging a block transfer with a byte + * transfer. + */ +s32 i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client, + u8 command, u8 length, u8 *values) +{ + u8 i = 0; + int status; + + if (length > I2C_SMBUS_BLOCK_MAX) + length = I2C_SMBUS_BLOCK_MAX; + + if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) + return i2c_smbus_read_i2c_block_data(client, command, length, values); + + if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA)) + return -EOPNOTSUPP; + + if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_WORD_DATA)) { + while ((i + 2) <= length) { + status = i2c_smbus_read_word_data(client, command + i); + if (status < 0) + return status; + values[i] = status & 0xff; + values[i + 1] = status >> 8; + i += 2; + } + } + + while (i < length) { + status = i2c_smbus_read_byte_data(client, command + i); + if (status < 0) + return status; + values[i] = status; + i++; + } + + return i; +} +EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data_or_emulated); + #if IS_ENABLED(CONFIG_I2C_SLAVE) int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb) { diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 5aea07137218..768063baafbf 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -121,6 +121,9 @@ extern s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client, extern s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, u8 command, u8 length, const u8 *values); +extern s32 +i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client, + u8 command, u8 length, u8 *values); #endif /* I2C */ /** -- cgit v1.2.3-70-g09d2